The invention concerns a method for coating the inside of pipes and similar longitudinally stretched hollow objects according to the generic terms of claim 1. The invention also concerns a coating system for the coating of the inside of pipes and similar longitudinally stretched hollow objects according to the generic terms of claim 2.
The pipe line network for the gas supply as well as water and sewer lines of towns and municipalities usually consist of steel pipes that are welded together. While pipes in newer pipe networks have been given an interior coating of e.g. Polyurethane by the manufacturer to protect against corrosion, older pipes do not feature such an interior protective coating and are therefore subject to corrosion which in the course of their operation can lead to leaks. Often, such pipelines are being replaced by a new pipeline after a long operation period. To lay new pipes however is time consuming and expensive, especially when it requires work in the ground or on streets. For this reason, it is aspired that pipes and similar longitudinally stretched hollow objects can be restored from within by giving the inner surface a suitable coating. If the pipes are sufficiently large enough in diameter, suitable machines with spray devices can be inserted and with their help the inner wall can be coated with the necessary Polyurethane or with another coating.
It is also known too first of all test underground pipe lines for eventual damage with a device that rests on the pipe walls. With a post-ceding device the damaged areas are re-coated and repaired. Such a device is known from the U.S. Pat. No. 4,691,728. Similar procedures are known from the PCT WO 96/06298 and PCT WO 96/06299. A process that works on concrete is subject of the DE-OS 14 50 384. In addition, from the DE 196 41 887 A1 a device is known for the thermal coating of the interior of positioned pipes. A motor driven pipe vehicle features a flexible work head at its end which holds a sand blaster jet or a welding torch. The vehicle is driven into the interior of the pipe which first of all will be blasted with the help of the sand blaster jet and then coated with a metal by the means of the welding torch whereas welding material and other coating substances will be added. A coating system that can be driven inside the pipe is described in the DE 198 41 891 A1, where the vehicle features a distributor, which more or less exactly applies the coating to the inner wall. A defined coating of the pipe is therefore not mentioned especially since the vehicle can only be moved towards one direction via a rope. A vehicle pulled by a section of piping is known from the EP-A-O 145 266. The vehicle consists of two parts and runs on fixed, non-adjustable skids, features a camera that precedes the vehicle in the main travel direction and which can only extend the rotor sprayer by a minimal degree against the travel direction to correct eventual mistakes immediately. The section of piping is being rolled onto or off a power driven spool without guidance.
The invention has the task to create a method and a coating device with which an interior coating of pipes and similar longitudinally stretched hollow objects can be achieved that can be defined and adapted to the individual conditions of the interior wall of the pipe.
The task is solved according to the invention by the characteristics of the typifying parts of claim 1.
With such a method, it is first of all possible that a defined inner coating can be applied because the process can continuously be monitored and corrected. The fact that the vehicle is moved through the pipe via the section of piping and exclusively via the section of piping, it is ensure that the section of piping into which the various components are pumped from the storage containers to the deployment location is always tight so that operational disruption through a bend or similar circumstances cannot take place. The vehicle and therefore also the distributor are always positioned in the middle of the pipe or the duct so that it is guaranteed that the mixed components from the distributor or the corresponding material always travel the same distance and settle evenly on the inner wall. The vehicle is being pulled forward via the section of piping, however, with a suitable device it can also be pulled in opposite direction so that flaws detected through monitoring can be corrected immediately, meaning without traveling long distances. Thus, a continuously even coating or securing of the inner wall of the pipe is guaranteed. The section of piping is safe from any bends or other disruptions and can foremost ensure a smooth movement of the vehicle which is additionally supported by the tensile design. The section of piping which carries the different components as well as compressed air and electricity remains undisturbed during the rolling on and off process because the section of piping in the tensile design also has an appropriate stability. Moreover it is intended in addition that the section of piping that moves the vehicle is guided onto and off the spool which also serves as a drive and thus it always remains connected with the coating agent storage containers. This special method ensures that even with a short noticed stop of the distributor or standstill of the vehicle the coating process can immediately continue after the vehicle continues to move. The necessary coating material but of course also the additional components are always readily available.
To complete the procedure, a coating system to coat the inside of pipes and similar longitudinally stretched hollow objects is intended which is equipped with a vehicle that is guided along the inner wall of the pipe by a drive and which features a distributor for the coating agent. The vehicle is connected with at least one coating agent storage container via a flexible section of piping whereas the section of piping is connected with a spool positioned outside the pipe whereas according to the invention the spool which serves as a tensile drive via the section of piping and which features a drive and a central, pipe-shaped spool axis whose at least one free end is equipped with a sealed pivotal connector at whose solid part at least one feed line from a coating agent storage container comes in and whose part that is connected with the pivotal part of the spool is connected to one of the product lines in the section of piping which in turn forms the tensile section of piping together with if necessary additional for the operation of the vehicle required supply lines. The section of piping can be rolled off the spool. The vehicle then also features a camera car and a rope on the side where the rotating distributor is located. Thus a coating system has been created which first of all can be pulled in one direction through the pipe or the underground duct evenly and without disruptions via the spool featuring the drive and the section of piping. Since the spool is positioned on the ground, special safety measures which otherwise would have to be considered do not have to be followed. Therefore the drive can be very simple in its design. A direct and constant connection of the vehicle and the distributor with the coating agent storage container is possible via the pivotal connector. The same is true of course with multiple storage containers. The section of piping itself is tensile so that there are no relaxed portions within the piping and thus no irregular operation of the vehicle. On one side the vehicle is connected with the section of piping and on the opposite side with a rope where also a camera cart can be attached which can monitor the coating process continuously and can ensure that when mistakes occur, for example irregular coating or missing sections of coating, the vehicle can immediately be stopped and pulled in the opposite direction in order to correct the mistake immediately while the process is being monitored.
In order to ensure an even rolling up and rolling off of the section of piping onto the spool over extended time and with multiple rolling up processes, the invention intends that the drive of the spool and the drive of a pair of preceding pressure rollers feature an electronic control which match the even pulling force one the one hand and the speed to roll up the section of piping on the other hand. Thus, over extended time, the powered spool can be used as the exclusive drive for the vehicle that is to be moved in the duct or in the pipe whereas the preceding pair of pressure rollers ensure the even rolling on and rolling off process as well as the even supply of section of piping.
According to further development it is intended that two pairs of pressure rollers are intended which are positioned one after the other towards the pulling motion and of which each features one pressure roller that is powered whereas the other pressure roller follows due the frictional pressure of the coating surface of the section of piping while the drive of the spool is built so that it follows the drive of the pairs of pressure rollers and at least one pair of pressure rollers can be extended parallel to the spool axis preferably on a carriage. Thus the section of piping can be evenly rolled on and off while it is ensured that the section of piping is also evenly moved between the spool and the pairs of pressure rollers while at the same time the rolling up process is facilitated because the pairs of pressure rollers move back and forth in front of the actual spool in such a way that the section of piping can always be rolled on tightly together onto the spool or rolled off the spool.
The even distance of the vehicle to the inner wall is ensured by the fact that the vehicle features a casing with six or more in radial direction extended gliding skids whose contact surface can be set towards the longitudinal middle axis of the vehicle. Thus the necessary adaptation to the changing diameter of the pipe can take place while it is thinkable that the gliding skids feature corresponding rollers or other glide media if this is deemed necessary and useful.
An even coating of the inner wall of the pipe or duct cannot be ensured by a simple spraying on of the coating material because the rotating distributor can also easily apply coating material onto already applied coats. In order to ensure most optimal coating it is intended that the rotating distributor is designed as a rotation symmetrical pot with outlet openings and that it features a pipe which leads into the inside of the pot and is fixated opposite to the casing of the vehicle and features a beveled open end piece whereas as the slanted opening points outwards to the closest area of the inside wall of the pot. Due to the outlet openings which are differentiated in at least two groups, it is possible to achieve a sufficient thickness of the coating as well on critical parts of the inside of the pipe such as at steps, ledges or inward pointed elevations. In relation to this effect it is especially advantageous when the outlet openings of the first group are tilted forward in relation to the longitudinal axis of the vehicle or the pipe and the outlet openings of the second group are tilted backward in relation to the longitudinal axis of the vehicle or the pipe. In this case, for example with inwards pointed elevations on the inside wall of the pipe the corners of such ledges which are pointed backwards in relation to the direction of the vehicle will be reached by the forwards pointed coating material jet while on the other hand the corners that point forwards in relation to the direction of the vehicle are reach by the coating material jets that face backwards so that overall, even at such critical points, a sufficient coating can be achieved. The outlet openings are preferably mostly cylindrically shaped drillings in the material of the distributor. The drillings allow a coating jet to be exactly defined in terms of its exit angle. The rotation symmetrical pot of the distributor prevents an uncontrolled release of coating material because the diameter of the inner wall at the open end of the pot is less than at the axial portion of the inner wall from where the distribution outlets start. Due to the exact placement of the pipe end inside the pot it is ensured that the transportation of the coating material happens on the shortest distance into all areas in the pot that feature outlet openings. Also, it is prevented that the coating material gets into areas where it could be distributed in an uncontrolled fashion for example at the open rim of the pot.
Another useful design intends that the rotating distributor is designed to function as a spray-gun with a radial positioned outlet opening and integrated mixer and that the shaft of the pivotal drive which turns the spray gun features a media through put or is a media through put. Thus is it possible for the first time, specifically, and in terms of the surrounding quasi continuously, to apply the coating agent without running the danger that an application of a coating agent is too thick or that a double application through the jets would cause the coating material to drip or to run. Instead, an exact, predetermined amount of coating material or two component mixture is applied onto the inner wall of the pipe by the spray gun which proceeds with the coating process in a spiral-like motion because the vehicle is moved evenly along the inside of the pipe. Due to the special design it is possible to select the thickness of the coating in such a way that when the connecting point is reached after one full turn of the spray gun the two component mixture is hardened enough that dripping or running is no longer possible. It is especially advantageous, however, that with a spray gun according to the invention the coating process can be disrupted at any time because the mixing of the two components happens inside the spray gun, and to be exact, in the spray head, so that after the appropriate off-time usually the coating (process) can be continued without any problems. This can be achieved for example by the fact that the compressed air that is already transported any way is used to clean the gun so that the completely clean spray gun is ready to continue the coating process. Thus, it is possible for example to plan the coating in sections and thus only in the areas that have damages in order to then move the entire vehicle to the next location and to continue the spraying again. For the first time it is therefore possible without driving back and forth for several meters or to spray more then 100 meters in sections because liners or other similar objects do not have to be used.
According to another useful design of the invention it is intended that the media through put is designed as a cylinder casing with a component connector for the two components and the compressed air connector and that the cylinder casing houses the shaft which is connected with the compressed air powered pivotal drive and that the shaft features outer ring channels and axial sack drillings that correspond with the connectors. The two components as well as the compressed air are inserted into the rotating spray gun via the media through put without causing a strain on the section of piping. The two components and the compressed air are transferred gently from the distribution station above ground to the job site inside the pipe to the be induced through the media through put into the spray gun to be mixed there and sprayed on. As it is seen in the characteristics in the claims section, the components can really be transported separately until close to the mixing location upon which they are being transported all the way to the handle of the spray gun. It is an advantage that the compressed air, which is also needed for other purposes that will be explained later, is used to turn the shaft and thus the spray gun. Via the compressed air the rotation speed can be set so intricately that the previously described even application effect can always safely be achieved.
The vehicle is moved in the pipe line or the duct via the section of piping which can be rolled up. On the one hand to enable an exact positioning of the vehicle in the pipe and also to take care of corrections, the invention intends that on the free end of the spray gun a flexible rope attachment piece for a rope is positioned that can be pulled in opposite direction. The rope that pulls in the opposite direction gives way enough that the vehicle can be moved in its intended direction but can also be activated in such a way that the vehicle moves backwards in its intended space or in other words is pulled backwards. A strain on the rope is being avoided because a pivotal head is intended between the turning spray gun and the rope pulling in the opposite direction so that the spray gun turns without transferring this motion onto the rope.
The portrayed section of piping can serve in a double function due to the fact that it consists of the two separate product lines which can be heated and two partial shells and a middle piece which features channels or partial channels for the product lines and additional support lines. Thus, a sufficiently stable enough layer can be placed around the product lines and the supply lines which for once takes care of the fact that the necessary pulling forces are transferred but that at the same time an isolation of the inner lines takes place which ensures a flawless operation of the coating system. Only when both products are transferred to the job site at the right temperature, a correspondingly fast and safe hardening at the inner wall of the pipe or the duct wall is required and accordingly possible. Accordingly, there are channels for the products lines intended in the lower half shell. The other supply lines are either arranged around the product lines or mostly in the upper half shell so that after integrating the appropriate lines the two partial shells and the middle piece can be inserted into each other and fixated in such a way that an even operation of the entire coating system is guaranteed. To connect the two partial shells that can be integrated and that enclose the middle piece, it is intended that the two partial shells are connected via a groove-spring connection, the middle piece and the product and supply lines fixated and connected with each other. The groove-spring connection can easily be complemented for which usually glue or other similar materials are inserted into the groove, so that the insertion of the spring enables a simple and safe connection. It is also thinkable that groove and spring are designed to correspond with each other so that by putting (them) together a first fixation is achieved.
An additional design of the invention intends that the rotating distributor features a radial positioned and executing outlet opening which corresponds with an atomizer air spray jet which is fitted with an airflow change nut that influences the spray angle of the media output. Via such a designed rotating distributor it is possible due to the corresponding air spray jet to wrap a layer of air around the individual coating jet which therefore guides the two component mixture exactly onto the inner wall of the pipe that is to be restored. Due to the air layer the over-spray of the two component mixture is also made more difficult. Depending on the shape of the air ring channel around the coating jet it can be worked exactly so that the air channel is widened just prior to the jet hitting the wall so that material over-sprays can be prevented. It is advantageous that via the air jet change nut the spray angle can always be changed and thus to accommodate the given situation. If for example the distance between the outlet opening and the pipe wall is small it usually is advantageous when a large spray angle is used while with larger distances the spray angle gets smaller or is small in order to guide the media jet exactly onto the inner wall of the pipe. Thus, it is thinkable that the air pressure change nut is either remotely set or set prior to putting the system underground in order to select a most exact definition of the media jet in connection with the air distribution jet.
Additionally it is intended that the rotating distributor consists of a supporting pipe with interior mixer which is connected with the spray head of the spray gun, an angled pipe with the outlet opening and the air pressure regulating nut whereas in the end piece of the angled pipe which points towards the inner wall there is an additional mixer reaching all the way into the outlet opening and whereas the atomizer air jet is detachably connected with the angled pipe and consists of two jet parts which are connected via a thread and of which the jet part that is positioned at the free end is designed as the air regulating nut. The design is therefore appropriately simple and thus can be manufactured cost effectively enough that it can be exchanged if necessary. According another useful design which is detailed in a later part of this documentation it is possible to blow out the distributor in order to, even with slightly longer breaks, prevent the caking of the two component mixture inside the distributor or inside the supporting pipe and the air jet. The previously described simple design of the rotating distributor still facilitates a long mixing process for the two components so that with exiting the outlet opening the necessary requirements for a fast adhesion and setting of the two component mixture are in any case fulfilled. After the re-routing of the previously mixed or pre-mixed two component mixture the material is then pushed through the second mixer and is handled intensively enough that the previously described optimized amalgamation is given when exiting out of the exit jet. An exchange of the air jet at the end of the supporting pipe and the angled pipe is possible because the air jet is detachably connected with the angled pipe and consists of two jet parts which are connected via a thread of which the jet part which is positioned at the free end is designed as the air regulating nut. With that the regulation of the coating jet is easily possible because only the air pressure regulating nut, thus the jet part which is positioned at the free end, has to be turned on the thread in order to regulate the angle of the jet to correspond with the situation.
The compressed air that is necessary to form the air in layer is added in the shortest possible way and that is because that the jet part that is connected with the angled pipe features an air connector and an air distribution chamber which is connected via axial air channels with a second air distribution chamber in the air pressure regulating nut, whereas a connector for compressed air is intended in the area of the spray head which via a pivotal connector ensures a continuous supply of air and which can be connected between the supporting pipe or the mixer and the medium valves. Due to the positioning of the air chambers it is ensured that with exiting from the exit ring channel an even air layer is being formed so that outbursts of the two component mixture can be prevented. For that, the second air chamber in the air pressure regulating nut is especially important, whereas it is shaped like a half dome and in such a way that the lowest point points toward the exit ring channel so that compressed air is being released in this area and thus exits appropriately. Thus, the compressed air can specifically enter in this area and can exit appropriately. An especially specified and even air layer is put around the coating jet. Thus, it is also thinkable to change the thickness of the wall of the exit ring channel, however, for this the air pressure regulating bolt would have to be equipped with a special feature. Usually, it is sufficient if the once set or pre-determined exit ring channel ensures that a sufficiently thick air coat is created whereas of course the exit speed of the compressed air from the exit ring channel has also to be taken into consideration. The rotating distributor is blown out at or shortly prior to standstill in order to use it again without any problems. Through the rotating connector it is ensured that the compressed air flows continuously and not only when the rotating drive has come to a standstill. This has the advantagexe2x80x94as further explained later in the textxe2x80x94that the connector for the compressed air can also simultaneously be used for the supply of the air jet.
The section of piping can advantageously be used for the supply and for the drive of the vehicle by integrating product lines and electrical supply lines in a highly resistant flexible tube thus building the section of piping. At the end facing the vehicle the section of piping is air tightly sealed by a cover or facing the tube spool side it is air-tightly sealed by a cover featuring a terminal block and at the same time it is configured to absorb tensile forces. The product lines which transport the two components of the coating material point towards each other in the outlet opening preceding the mixer which also features a compressed air supply line with an air jet that connects in a right angle to it. Such a designed section of piping makes it possible to pull the required product lines, supply lines and other cable or other similar items into the highly resistant flexible tube and to store them therein. In the event that the 150 m long or longer section of piping shall be used to pull the vehicle through the duct or the pipe, the section of piping or better the highly resistant flexible tube is filled with compressed air and inflated to the extend that the highly resistant wall effectively protects the product lines and supply lines within and also ensures the necessary isolation. Through the air that is built up in the highly resistant tube the product lines are kept at temperature as much as necessary because the air can act as an isolator and thus be supported by the wall of the tube. In addition, tensile forces can be applied without running the danger that the product lines or supply lines can be overly strained and effected by the tensile forces in any way. It is also advantageous that weight can be reduced by omitting a section of piping that fully consists of material. It is especially advantageous that the manufacturing of such a protective coating for the product lines, electrical supply lines and other lines is expressively simple because only a highly resistant tube is necessary which doesn""t require any preparation procedures. It is only fixated through covers at the ends and/or terminal blocks and equipped in such a way that it can on the one hand be connected with the vehicle and on the other hand connected with the roll up device. The coating material is being pumped through the product lines to the vehicle and is mixed here in such a way that the two components are applied at the same time to the inner wall of the pipe or duct. It is followed by a pressure mix with injector effect because the compressed air which is induced at the same time, therefore the mixed or pre-mixed coating material is pressed and pushed into the outlet opening and thus into the jet so that the coating material is thrown onto or sprayed onto the inner wall as a complete mixture. It has been found that with the described design the mixing of both components can happen on short distances and fast so that correspondingly smaller built devices can be used. The individual component material that exits from opposite from each other positioned openings of the product lines is swept away by the air stream and is skillfully mixed and increased in speed so that it can even be applied to pipes featuring larger diameters without bouncing off the inner wall. To fulfill this purpose, the product lines transport the coating material under appropriate pressure. For example, the component material which is required in large quantities is pushed through the section of piping with 100 bar whereas the component material that is required in a lesser quantity is transfer with 50 bar to be joint at the mixer. By changing the pressure the quantity can thus be changed and adapted to meet the individual requirements whereas depending on the applicable situation and the coating material that is to be used the quantity of the component is predetermined and thus also the pressure conditions relating to the two product lines.
Previously in the text it has been indicated that the highly resistant flexible tube is sealed by covers at the ends and that it is also configured to absorb tensile forces. At the same time the necessary also tensile connection between this part and the highly resistant tube is ensured by the fact that the cover or the terminal block is connected with a tube spout which is positioned far into the tube and held by an outer teethed link and which is equipped with corresponding ring grooves to hold an O-ring. The tube spouts with their outer teethed links are inserted into the tube prior to it being pressurized. Thus, a positioning is possible, whereas it is practically impossible to pull out the tube spout due to the outer teethed link and this effect can be increased if necessary by tube clamps. With the appropriate fixation of the tube spouts in the highly resistant tube, the opportunity is created to tightly attach those tube spouts at the cover or the terminal block especially to screw them in. The necessary sealing effect in the area of the cover and the terminal block is created by the O-rings. Thus the area between cover and tube spout is effectively sealed so that the compressed air cannot unintentionally escape. Moreover, the compressed tube or better the tube that is filled with compressed air remains in its secured position so that the other contained supply lines are undisturbed and protected.
The tube which is sealed on both ends by the covers or the terminal block is to be inflated when in operation in order to ensure the appropriate safety of the product lines, compressed air line and supply lines and to perfectly absorb the tensile forces. For this the invention intends additionally that the cover on the side of the tube spool features a connector drilling for a low pressure line to add compressed air, preferably ranging from 2 to 4 bar and that the drilling features a sealing coating that works together with the outer wall of the product lines, compressed air line and supply line. With this low pressure line, compressed air is guided into the inside of the tube so that it can inflate due to the fact that it is closed and sealed on both ends with the covers so that therefore it obtains the necessary stiffness or that its stiffness is ensured. The coating can of course also be assigned to the individual supply lines and other lines, however, it is really only necessary in the area of the insertion in the area of the drilling so that it is more useful to equip the inner wall appropriately. The appropriate coating has the additional advantage that an even insertion or pulling through motion of the supply and other lines is facilitated.
The section of piping that is being used or the appropriate tube has a total length of 150 meters or more, and it is rolled up on an appropriate tube spool or is rolled off of it depending on which the direction the vehicle moves towards. On the one hand to absorb tensile forces that develop and on the other hand to optimize the flexibility of the tube in the best way it is intended that the wall or the highly resistant tube features a reinforcement whereas this reinforcement does not necessarily have to be designed in a spiral shape but can also consist of rings that are either set on the outside of the tube or are integrated in the tube or are positioned on the inside in order to ensure the appropriate stability. The spiral shaped design as well as the ring shaped design ensures that the tube can be rolled up in any case.
The invention distinguishes itself especially by the fact that a method for the interior coating of pipes and similar longitudinally stretched hollow objects has been designed and that in addition a coating system with which the application of the coating material is enabled continuously and in such a fashion that the coating procedures in sections of 150 metes or more have an even and flawless result. The vehicle is pulled evenly through the pipe or duct that is to be coated by the powered section of piping which can absorb the tensile forces and which is to be pulled evenly through the duct or the pipe by the especially designed spool. Loops or entanglements are not possible so that an even supply of the vehicle and the distributor is ensured. The section of piping is simple in design and can be inflated so that the interior product lines and supply lines are very safe and that at the same time it is possible to keep the temperature (warm) so that the coating components can be transferred safely to the distributor even over great distances. The vehicle is always guided in the center of the pipe, can be moved in both directions and allows an immediate supervision of the coating effort so that mistakes can be corrected very quickly and on the shortest distance possible.
Additional details and advantages of the invented object can be found in the following description of the corresponding drawings where a preferred design example is depicted with the necessary details and individual parts. It is shown in: